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5 results on '"Guy, Julien"'

1. Redshift-dependent RSD bias from intrinsic alignment with DESI Year 1 spectra.

Author

Lamman, Claire, Eisenstein, Daniel, Aguilar, Jessica Nicole, Ahlen, Steven, Brooks, David, Claybaugh, Todd, de la Macorra, Axel, Dey, Arjun, Dey, Biprateep, Doel, Peter, Ferraro, Simone, Font-Ribera, Andreu, Forero-Romero, Jaime E, Gontcho, Satya Gontcho A, Guy, Julien, Kehoe, Robert, Kremin, Anthony, Le Guillou, Laurent, Levi, Michael, and Manera, Marc

Subjects
EMISSION-line galaxies, DARK energy, LARGE scale structure (Astronomy), STATISTICAL correlation, REDSHIFT
Abstract

We estimate the redshift-dependent, anisotropic clustering signal in the Dark Energy Spectroscopic Instrument (DESI) Year 1 Survey created by tidal alignments of Luminous Red Galaxies (LRGs) and a selection-induced galaxy orientation bias. To this end, we measured the correlation between LRG shapes and the tidal field with DESI's Year 1 redshifts, as traced by LRGs and Emission-Line Galaxies. We also estimate the galaxy orientation bias of LRGs caused by DESI's aperture-based selection, and find it to increase by a factor of seven between redshifts 0.4−1.1 due to redder, fainter galaxies falling closer to DESI's imaging selection cuts. These effects combine to dampen measurements of the quadrupole of the correlation function (ξ2) caused by structure growth on scales of 10–80 h −1 Mpc by about 0.15 per cent for low redshifts (0.4 < z < 0.6) and 0.8 per cent for high (0.8 < z < 1.1), a significant fraction of DESI's error budget. We provide estimates of the ξ2 signal created by intrinsic alignments that can be used to correct this effect, which is necessary to meet DESI's forecasted precision on measuring the growth rate of structure. While imaging quality varies across DESI's footprint, we find no significant difference in this effect between imaging regions in the Legacy Imaging Survey. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Analysis of the impact of broad absorption lines on quasar redshift measurements with synthetic observations.

Author

García, Luz Ángela, Martini, Paul, Gonzalez-Morales, Alma X, Font-Ribera, Andreu, Herrera-Alcantar, Hiram K, Aguilar, Jessica Nicole, Ahlen, Steve, Brooks, David, de la Macorra, Axel, Doel, Peter, Forero-Romero, Jaime E, Guy, Julien, Kisner, Theodore, Landriau, Martin, Miquel, Ramon, Moustakas, John, Nie, Jundan, Poppett, Claire, Tarlé, Gregory, and Zhou, Zhimin

Subjects
REDSHIFT, DARK energy, QUASARS, SIGNAL-to-noise ratio, ABSORPTION, GALAXIES, PHYSICAL cosmology
Abstract

Accurate quasar classifications and redshift measurements are increasingly important to precision cosmology experiments. Broad absorption line (BAL) features are present in 15–20 per cent of all quasars, and these features can introduce systematic redshift errors, and in extreme cases produce misclassifications. We quantitatively investigate the impact of BAL features on quasar classifications and redshift measurements with synthetic spectra that were designed to match observations by the Dark Energy Spectroscopic Instrument (DESI) survey. Over the course of 5 yr, DESI aims to measure spectra for 40 million galaxies and quasars, including nearly three million quasars. Our synthetic quasar spectra match the signal-to-noise ratio and redshift distributions of the first year of DESI observations, and include the same synthetic quasar spectra both with and without BAL features. We demonstrate that masking the locations of the BAL features decreases the redshift errors by about 1 per cent and reduces the number of catastrophic redshift errors by about 80 per cent. We conclude that identifying and masking BAL troughs should be a standard part of the redshift determination step for DESI and other large-scale spectroscopic surveys of quasars. [ABSTRACT FROM AUTHOR]

Published
2023
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3. The Completed SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations with Lyα Forests.

Author

Bourboux, Hélion du Mas des, Rich, James, Font-Ribera, Andreu, de Sainte Agathe, Victoria, Farr, James, Etourneau, Thomas, Goff, Jean-Marc Le, Cuceu, Andrei, Balland, Christophe, Bautista, Julian E., Blomqvist, Michael, Brinkmann, Jonathan, Brownstein, Joel R., Chabanier, Solčne, Chaussidon, Edmond, Dawson, Kyle, González-Morales, Alma X., Guy, Julien, Lyke, Brad W., and de la Macorra, Axel

Subjects
OSCILLATIONS, ACOUSTIC measurements, QUASARS, REDSHIFT, FORECASTING
Abstract

We present a measurement of baryonic acoustic oscillations (BAOs) from Lyα absorption and quasars at an effective redshift using the complete extended Baryonic Oscillation Spectroscopic Survey (eBOSS). The 16th and final eBOSS data release (SDSS DR16) contains all data from eBOSS and its predecessor, the Baryonic Oscillation Spectroscopic Survey (BOSS), providing 210,005 quasars with zq > 2.10 that are used to measure Lyα absorption. We measure the BAO scale both in the autocorrelation of Lyα absorption and in its cross-correlation with 341,468 quasars with redshift zq > 1.77. Apart from the statistical gain from new quasars and deeper observations, the main improvements over previous work come from more accurate modeling of physical and instrumental correlations and the use of new sets of mock data. Combining the BAO measurement from the auto- and cross-correlation yields the constraints of the two ratios and , where the error bars are statistical. These results are within 1.5σ of the prediction of the flat-ΛCDM cosmology of Planck (2016). The analysis code, picca , the catalog of the flux transmission field measurements, and the Δχ2 surfaces are publicly available. [ABSTRACT FROM AUTHOR]

Published
2020
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4. Cosmological implications of baryon acoustic oscillation measurements

Author

Aubourg, Éric, Bailey, Stephen, Bautista, Julian E., Beutler, Florian, Bhardwaj, Vaishali, Bizyaev, Dmitry, Blanton, Michael, Blomqvist, Michael, Bolton, Adam S., Bovy, Jo, Brewington, Howard, Brinkmann, J., Brownstein, Joel R., Burden, Angela, Busca, Nicolás G., Carithers, William, Chuang, Chia-Hsun, Comparat, Johan, Croft, Rupert A. C., Cuesta, Antonio J., Dawson, Kyle S., Delubac, Timothée, Eisenstein, Daniel J., Font-Ribera, Andreu, Ge, Jian, Le Goff, J. -M., Gontcho, Satya Gontcho A., Gott, J. Richard, Gunn, James E., Guo, Hong, Guy, Julien, Hamilton, Jean-Christophe, Ho, Shirley, Honscheid, Klaus, Howlett, Cullan, Kirkby, David, Kitaura, Francisco S., Kneib, Jean-Paul, Lee, Khee-Gan, Long, Dan, Lupton, Robert H., Magaña, Mariana Vargas, Malanushenko, Viktor, Malanushenko, Elena, Manera, Marc, Maraston, Claudia, Margala, Daniel, McBride, Cameron K., Miralda-Escudé, Jordi, Myers, Adam D., Nichol, Robert C., Noterdaeme, Pasquier, Nuza, Sebastián E., Olmstead, Matthew D., Oravetz, Daniel, Pâris, Isabelle, Padmanabhan, Nikhil, Palanque-Delabrouille, Nathalie, Pan, Kaike, Pellejero-Ibanez, Marcos, Percival, Will J., Petitjean, Patrick, Pieri, Matthew M., Prada, Francisco, Reid, Beth, Rich, James, Roe, Natalie A., Ross, Ashley J., Ross, Nicholas P., Rossi, Graziano, Rubiño-Martín, Jose Alberto, Sánchez, Ariel G., Samushia, Lado, Génova-Santos, Ricardo Tanausú, Scóccola, Claudia G., Schlegel, David J., Schneider, Donald P., Seo, Hee-Jong, Sheldon, Erin, Simmons, Audrey, Skibba, Ramin A., Slosar, Anže, Strauss, Michael A., Thomas, Daniel, Tinker, Jeremy L., Tojeiro, Rita, Vazquez, Jose Alberto, VIEL, MATTEO, Wake, David A., Weaver, Benjamin A., Weinberg, David H., Wood-Vasey, W. M., Yèche, Christophe, Zehavi, Idit, Zhao, Gong-Bo, BOSS Collaboration, USA, Universitat de Barcelona, AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Departamento de FisicaTeorica e IFT-UAM/CSIC, Universidad Autonoma de Madrid (UAM), Laboratoire d'Astrophysique, Ecole Polytechnique Fédérale de Lausanne (EPFL), Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Centre Hospitalier Universitaire de Dijon - Hôpital François Mitterrand (CHU Dijon), Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), McMaster University [Hamilton, Ontario], Department of Physics and Astronomy [Irvine], University of California [Irvine] (UCI), University of California-University of California, Ecole Polytechnique Fédérale de Lausanne (EPFL), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universidad Santiago de Chile, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Département de Physique des Particules (ex SPP) (DPP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Lawrence Berkeley National Laboratory [Berkeley] (LBNL), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Shandong University, Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), EPFL Laboratoire d’astrophysique, Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Universidad de Chile = University of Chile [Santiago] (UCHILE), University of St Andrews. School of Physics and Astronomy, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universidad Autónoma de Madrid (UAM), University of California [Irvine] (UC Irvine), University of California (UC)-University of California (UC), and Département de Physique des Particules (ex SPP) (DPhP)

Subjects
Nuclear and High Energy Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), LARGE SCALE STRUCTURE, gr-qc, COSMOLOGICAL PARAMETERS, Cosmic microwave background, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Atomic, General Relativity and Quantum Cosmology, Cosmology, High Energy Physics - Experiment, purl.org/becyt/ford/1 [https], High Energy Physics - Experiment (hep-ex), symbols.namesake, Particle and Plasma Physics, Settore FIS/05 - Astronomia e Astrofisica, Dark energy, Nuclear, Planck, QC, Physics, Quantum Physics, Cosmologia, hep-ex, Astrophysics::Instrumentation and Methods for Astrophysics, Molecular, 3rd-DAS, purl.org/becyt/ford/1.3 [https], Espectroscòpia de microones, Nuclear & Particles Physics, Redshift, Baryon, QC Physics, 13. Climate action, astro-ph.CO, symbols, Microwave spectroscopy, Baryon acoustic oscillations, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astronomical and Space Sciences, Astrophysics - Cosmology and Nongalactic Astrophysics, Hubble's law, BARYON ACCOUSTIC OSCILLATIONS
Abstract

We derive constraints on cosmological parameters and tests of dark energy models from the combination of baryon acoustic oscillation (BAO) measurements with cosmic microwave background (CMB) and Type Ia supernova (SN) data. We take advantage of high-precision BAO measurements from galaxy clustering and the Ly-alpha forest (LyaF) in the BOSS survey of SDSS-III. BAO data alone yield a high confidence detection of dark energy, and in combination with the CMB angular acoustic scale they further imply a nearly flat universe. Combining BAO and SN data into an "inverse distance ladder" yields a 1.7% measurement of $H_0=67.3 \pm1.1$ km/s/Mpc. This measurement assumes standard pre-recombination physics but is insensitive to assumptions about dark energy or space curvature, so agreement with CMB-based estimates that assume a flat LCDM cosmology is an important corroboration of this minimal cosmological model. For open LCDM, our BAO+SN+CMB combination yields $\Omega_m=0.301 \pm 0.008$ and curvature $\Omega_k=-0.003 \pm 0.003$. When we allow more general forms of evolving dark energy, the BAO+SN+CMB parameter constraints remain consistent with flat LCDM. While the overall $\chi^2$ of model fits is satisfactory, the LyaF BAO measurements are in moderate (2-2.5 sigma) tension with model predictions. Models with early dark energy that tracks the dominant energy component at high redshifts remain consistent with our constraints. Expansion history alone yields an upper limit of 0.56 eV on the summed mass of neutrino species, improving to 0.26 eV if we include Planck CMB lensing. Standard dark energy models constrained by our data predict a level of matter clustering that is high compared to most, but not all, observational estimates. (Abridged), Comment: 38 pages, 20 figures, BOSS collaboration paper; v2: fixed inconsistent definitions of DH, added references; v3: version accepted by PRD, corrected error resulting in significantly weaker constraints on decaying dark matter model

Published
2015

5. The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star.

Author

Andrew Howell, D., Sullivan, Mark, Nugent, Peter E., Ellis, Richard S., Conley, Alexander J., Le Borgne, Damien, Carlberg, Raymond G., Guy, Julien, Balam, David, Basa, Stephane, Fouchez, Dominique, Hook, Isobel M., Hsiao, Eric Y., Neill, James D., Pain, Reynald, Perrett, Kathryn M., and Pritchet, Christopher J.

Subjects
DARK energy, TYPE I supernovae, WHITE dwarf stars, ACCRETION (Astrophysics), REDSHIFT, METAPHYSICAL cosmology
Abstract

The accelerating expansion of the Universe, and the need for dark energy, were inferred from observations of type Ia supernovae. There is a consensus that type Ia supernovae are thermonuclear explosions that destroy carbon–oxygen white dwarf stars that have accreted matter from a companion star, although the nature of this companion remains uncertain. These supernovae are thought to be reliable distance indicators because they have a standard amount of fuel and a uniform trigger: they are predicted to explode when the mass of the white dwarf nears the Chandrasekhar mass of 1.4 solar masses (M\cirċ). Here we show that the high-redshift supernova SNLS-03D3bb has an exceptionally high luminosity and low kinetic energy that both imply a super-Chandrasekhar-mass progenitor. Super-Chandrasekhar-mass supernovae should occur preferentially in a young stellar population, so this may provide an explanation for the observed trend that overluminous type Ia supernovae occur only in ‘young’ environments. As this supernova does not obey the relations that allow type Ia supernovae to be calibrated as standard candles, and as no counterparts have been found at low redshift, future cosmology studies will have to consider possible contamination from such events. [ABSTRACT FROM AUTHOR]

Published
2006
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